Apple's iPhone 5 hit stores in a festive global rollout Friday, with long queues of devotees undeterred by a lukewarm welcome from experts for the smartphone and complaints about its new mapping system.

The lines of eager fans outside retail stores looked set to make the latest generation iPhone another commercial smash for the trend-setting US company, coming after Apple said it had received more than two million orders online.

Australians were the first to get their hands on the device. In Sydney the faithful filmed the experience on their iPhones and iPads as staff inside clapped and cheered when the doors opened at 8:00 am (2200 GMT Thursday).

But the event was also hijacked by companies looking for free publicity, with the first dozen or so in the queue wearing promotional T-shirts and caps or carrying advertising materials.

"Seven of us are here from our company, since midday Tuesday," said Todd Foot, 24, who was first in the line and works for an organisation that reviews mobile phones.

"We've actually had telephone hook-ups with the first in the lines in New York and London. It's been a bit crazy."

Compared to the iPhone 4S, Apple's new smartphone boasts a bigger display, stronger battery and faster connection to the latest 4G networks. It is lighter and slimmer, and contains tweaks designed to improve the user's experience.

But many analysts say Apple has fallen short as other companies such as Samsung improve rival offerings powered by Google's Android operating system.

"Unless Apple ups its device innovation game, we may be seeing Apple's iOS empire approaching its zenith," Tony Costa of Forrester Research said.

However, enthusiasm among early-bird shoppers was undimmed as iPhone 5 sales began too in Japan, Hong Kong and Singapore. Later Friday, sales will start in France, Germany, Britain, the United States and Canada.

Ryoho Yamashita, a 23-year-old student, had queued since midnight at a Softbank store in Tokyo and said there had been a celebratory atmosphere among those waiting.

"It's like a festival that I enjoy every year," he said, holding his new purchase as he acclaimed the smartphone's light weight and speed of connection.

In Hong Kong, grey marketeers pounced on anyone who emerged from the city's official Apple store, offering a premium for their phone in the hope of re-selling it for even more given shortages in the retail market.

"I paid about HK$8,000 ($1,030) for the iPhone just now. We'll sell it for around HK$9,000 to HK$10,000," said Suen, a reseller who refused to give his full name. The normal retail price starts at HK$5,588 in the Apple store.

In Singapore, staff at an Apple reseller were turning people away, having run out of phones within hours of opening.

In Tokyo, engineer Masaru Mitsuya, 30, shrugged off some shortcomings with the new iPhone's built-in iOS 6 operating system that have attracted heavy criticism online.

"On the whole the new product is better," he said. "But I know the mapping function is not great. A station suddenly appears in the sea or Korean characters appear. But I'll survive by downloading Google-made software."

Apple faces growing criticism from users around the world after it ditched a maps application made by its rival Google in favour of a native app that is reportedly riddled with errors.

A day after the new iOS 6 system was released, users from countries including the United States, Britain, China, France and Japan protested that the new maps misplace some landmarks and leave others off altogether.

The global launch could also be affected by a call from unions for staff at Apple's 13 stores in France to go on strike Friday over a pay dispute.

Apple, whose shares soared past US$700 in anticipation of the launch, says the iPhone 5 will be available in 100 countries by year's end.

Some analysts have tipped Apple to sell 10 million units globally in the opening days and 50 million before the end of 2012, giving a small but welcome boost to the US economy.